Madagascan rousette description

The Madagascan rousette (Rousettus madagascariensis) is the smallest of Madagascar’s three endemic fruit bats (3). Its body is greyish-brown on the upperparts, with reddish-brown tinges, and paler grey-brown on the underparts. The fur is quite long and dense, but shorter on the neck, throat and shoulders. The wings are relatively broad (2).

As in other fruit bats, the face of the Madagascan rousette is rather dog-like, with a pointed muzzle, large eyes, and fairly conspicuous, widely separated ears (2)(4). Although most fruit bats rely on sight and smell as their main senses, some members of the genusRousettus also use a rudimentary form of echolocation, producing high-pitched clicks with the tongue to help detect obstacles in their path. The association of the Madagascan rousette with cave roost sites suggests that this species is also likely to possess this ability (2)(4)(5).

Related species

Madagascan rousette biology

The Madagascan rousette feeds mainly on the juices of fruits, soft fruit pulp and nectar. It may play an important role in the forest as a pollinator and seed disperser (1)(2)(5)(9), particularly as its small size makes it the only fruit bat in Madagascar that can fly within intact forest (1)(3).

The rudimentary echolocation of this species is likely to be used only for orientation, with food being detected using vision and scent. The Madagascan rousette flies considerable distances each night in search of food (2)(9). It is also probably capable of longer-distance flights, and appears to be a rather mobile species that is readily able to disperse across the island (10). Emerging from caves at dusk puts the Madagascan rousette at risk of predation by owls and raptors (11).

This species may form roosts of up to several hundred individuals (2), although a single cave roost of over 5,000 has also been recorded (12). During the daytime, roosts are noisy and the bats are often restless, continually competing for the best positions. Fights are not uncommon (2)(5). In general, Rousettus species have extended breeding seasons which follow the rains, sometimes with two peaks each year (5). A study in the east of Madagascar found that the Madagascan rousette gives birth to a single young (9).

Madagascan rousette status

Madagascan rousette threats

The Madagascan rousette is believed to have undergone a decline of around 20 to 25 percent in recent decades. Although often the most commonly trapped species during scientific surveys, it is seriously threatened by overhunting (1)(3)(7)(13). Most hunting occurs at the roosts, by local people, with the bats caught in locally made traps or knocked down from the cave ceiling using sticks (1)(13).

The Madagascan rousette may also potentially be killed as a pest of fruit crops (1). Under Malagasy law, the Madagascan rousette is a game species, and as such only receives protection where it occurs in nature reserves, or where it roosts at sacred sites (1)(14). However, many reserves receive little real protection, and the national hunting season for bats is also largely ignored (7)(13).

Since fruit bats produce only a single offspring each year, they are particularly susceptible to overhunting (13). Forest destruction and degradation are likely to compound these problems (1)(7), although the extent to which the Madagascan rousette is impacted by deforestation is not yet fully understood (1).

Madagascan rousette conservation

The Madagascan rousette occurs in several protected areas within Madagascar, including Ankarana Special Reserve and Tsingy de Bemaraha National Park (1)(7)(15). However, roost sites are in need of more effective protection both within and outside of these areas, and cooperation with local communities is likely to be vital (1)(13).

Other recommended conservation actions for the Madagascan rousette include further studies into its biology and ecology, especially its reproductive behaviour (7). A number of organisations have already been active in investigating the diet and foraging behaviour of the Madagascan rousette, as well as investigating the patterns and impacts of hunting. Various environmental education programmes have also been initiated, to increase awareness of bat conservation amongst local communities (3)(14). However, unless the Madagascan rousette can be effectively protected against overhunting and the effects of habitat loss, it may become increasingly threatened in the future.

Glossary

Forest consisting mainly of deciduous trees, which shed their leaves at the end of the growing season.

Echolocation

Detecting objects by reflected sound. Used by bats and odontocete cetaceans (toothed whales, dolphins and porpoises) for orientation and to detect and locate prey.

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Gestation

The state of being pregnant; the period from conception to birth.

Pollinator

An animal that in the act of visiting a plant’s flowers transfers pollen grains from the stamen (male part of a flower) to the stigma (female part of a flower) of a flowering plant. This usually leads to fertilisation, the development of seeds and, eventually, a new plant.

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